[patch 3/4] mmu_notifier: invalidate_page callbacks

Two callbacks to remove individual pages as done in rmap code invalidate_page() Called from the inner loop of rmap walks to invalidate pages. age_page() Called for the determination of the page referenced status. If we do not care about page referenced status then an age_page c

[patch 3/4] mmu_notifier: invalidate_page callbacks for subsystems with rmap

Callbacks to remove individual pages if the subsystem has an rmap capability. The pagelock is held but no spinlocks are held. The refcount of the page is elevated so that dropping the refcount in the subsystem will not directly free the page. The callbacks occur after the Linux rmaps have been wal